I. Field of the Invention
The present invention relates generally to turbine engine lubrication systems and, more particularly, to such a lubrication system which utilizes a fuel-air mist as the lubricant.
II. Description of the Prior Art
All turbine engines include a turbine shaft which is rotatably mounted by a bearing assembly to a stationary support housing. Due to the nature of operation of the turbine engine, the turbine shaft necessarily rotates at high speeds. Consequently, the bearing assembly must not only be adequately lubricated but also cooled in order to prevent failure of the bearings. A bearing failure can result in destruction of the turbine engine.
The previously known turbine engine bearing lubrication systems, however, have proven inadequate in operation and/or expensive in construction. Typically, these previously known systems include oil pumps, external oil supply reservoirs, and associated components which continuously pump oil through the bearing assembly. The multiplicity of components within these previously known lubrication systems not only greatly increased the cost, but also the failure rate of such systems since failure of any of several components disabled the entire lubrication system. Since failure of the lubrication system often results in the destruction of the turbine engine, the previously known turbine engines typically included back-up or secondary oil systems which operated upon the failure of the primary lubrication system. These secondary lubrication systems increase not only the weight but also the overall cost of the turbine engine.
In an effort to overcome some of the above mentioned disadvantages of the previously known turbine engine lubrication systems, Wilkinson et al disclose in their U.S. Pat. No. 3,377,802 which issued on Apr. 16, 1968, a turbine engine lubrication system which utilizes compressed air mixed with oil to lubricate the turbine bearing assembly. The Wilkinson lubrication system, however, is a recirculatory lubrication system which collects and cools the oil lubricant in oil reservoirs. Consequently, Wilkinson retains much of the complexity of the other previously known turbine lubrication systems.